Gastric or intestinal ulcers are manifested essentially by a loss of substance from a mucosal epithelial covering without any tendency for spontaneous healing and by lesion of the gastric or intestinal, notably duodenal, wall. It is generally considered that gastric or intestinal, notably duodenal, ulcers result from a mismatch between aggressive factors, such as acid and peptic gastric secretions, and defensive factors, such as prostaglandin synthesis, mucus and the surface epithelium.
Apart from Helicobacter pylori, gastrointestinal ulcers are mainly drug-induced. Thus, aspirin and the non-steroidal anti-inflammatories (NSAIDs), such as ibuprofen, notably inhibit the cyclooxygenases, leading to a decrease in prostaglandin synthesis and secretion of protective gastrointestinal mucus. In consequence, the gastrointestinal mucosa is exposed to acid attack by the gastric secretions.
NSAIDs with increased selectivity with respect to type 2 cyclooxygenase (COX-2), which is mainly inflammatory, relative to COX-1, forming the COXIB class of medicinal products, have been developed. However, the clinical studies conducted to date indicate that the COXIBs also present an increased risk of development of gastrointestinal ulcers (Yeomans (2002) Journal of Gastroenterology and Hepatology 17:488-494), which might reflect the role of COX-2 in the repair of mucosal lesions (Halter et al. (2001) Gut 49:443-453).
Thus, the problem of gastrointestinal ulcers linked to NSAIDs is particularly acute for persons treated long-term with these compounds, for example for controlling joint pain and inflammation.
At present, the main treatments used for gastrointestinal ulcers linked to NSAIDs employ two types of compounds (Yeomans (2002) Journal of Gastroenterology and Hepatology 17:488-494; Florent et al. (1990) Acta Endoscopica 20: 427-439):
(i) inhibitors of gastric secretions: proton pump inhibitors, such as omeprazole, or antagonists of the H2 histamine receptors, such as cimetidine and ranitidine;
(ii) stimulators of mucus secretion, such as the prostaglandins, and notably misoprostol (Graham et al. (1988) Lancet 2:1277-1280).
However, none of these treatments is completely satisfactory.
Saccharomyces boulardii (Ultra-Levure®) is a particular strain of the yeast Saccharomyces cerevisiae. This probiotic is mainly indicated as a supplement to rehydration for the treatment of diarrhoea. Its usefulness has notably been established in children (Villarruel et al. (2007) Acta Paediatr 96:538-541; Szajewska et al. (2007) Aliment Pharmacol Ther 25:257-264) and for diarrhoea associated with taking antibiotics (Surawicz et al. (1989) Gastroenterology 96:981-988; Kotowska et al. (2005) Aliment Pharmacol Ther 21:583-590) or with infections with Clostridium difficile (Surawicz et al. (2000) Clin Infect Dis 31:1012-1017).